Attic. Arguably the most important space in the home to insulate is the attic. This is primarily because heat naturally rises, which means that the attic will hold a lot of the heat generated in the home. During the winter, having that heat escape through the attic will push up energy bills.
Before insulating, seal any air leaks and make roof and other necessary repairs. If it is located in a conditioned part of the house, also remember to insulate and air seal your attic access. Insulate and air seal any knee walls -- vertical walls with attic space directly behind them -- in your home as well.
If a house has NO insulation at all... generally its advised to insulate the attic first since that is generally accessible (eg through the attic access points) and heat rises. Second insulate the walls but that is more complicated since it entails accessing and filling each space between the wall joists.
Never place insulation close to water heaters, oil burners or anything hot. The backing is especially flammable and will be a major fire hazard for your home.
In addition to walls and attics, insulation should be installed in ceilings with unheated spaces, basement walls, floors above vented crawl spaces, cathedral ceilings, floors over unheated garages or porches, knee walls, and in between interior walls—especially bathrooms—as well as ceilings and floors.
One of the most important rules of insulation installation order is to install the thickest layer of insulation first, and then add thinner layers on top of it. This is because the thicker the insulation, the higher the R-value, and the more effective it is at preventing heat transfer.
Home energy experts tend to agree that the attic is the single most crucial site for insulation in the home. Hot air rises. If you have insufficient insulation in your attic, the air you've spent your hard-earned cash heating up will head to a place where you're least likely to benefit from it.
Moisture damage
This can occur due to leaks in the roof or foundation, inadequate ventilation, or high humidity levels inside a building. Moisture can cause the insulation material to become compressed and lose its effectiveness, leading to increased energy consumption and potential mold growth.
If installed incorrectly, moisture can become trapped between the facing and cause mold, rotting, and reduced R-value.
Exposed insulation is at risk of catching fire if not covered properly because it is extremely flammable. Installing a fire retardant plastic sheeting over insulation slows the fire damage rate in the case of an adverse event.
As for attic vs. wall insulation, always go for the attic. The largest pay back will be seen here. You would stop heat loss from natural convection and block solar gain (an increase in heat) in the attic, which can result in energy savings of 30 to 50 percent.
Before Installing Insulation
Check your local building code for R-value (insulation level) recommendations and any vapor barrier requirements that apply to your area. Seal gaps that allow unconditioned air into the space you're insulating. Pay attention to areas where plumbing, ductwork or wiring enter the space.
For new builds or if you are renovating, you may be asking yourself if you should insulate your ceiling or walls first. The best answer is both. Insulation is a once-only cost that makes your house more comfortable for it's entire lifespan, without another cent having to be spent.
The best way to insulate the inside of a ceiling depends on the type of ceiling and your specific needs. Spray foam insulation and batt insulation are two popular options. Spray Foam Insulation: This method involves spraying a liquid foam that expands and hardens.
Spray foam insulation is a good insulator in terms of keeping a room warm or cool. But its many downsides outweigh the benefits. These include, making it more difficult getting a mortgage, potential health issues, environmental damage, ventilation issues and a lower home valuation.
Many of us know what causes mould; when moisture is trapped in the rooms of you home. Sometimes, there is insufficient insulation in the walls, so mould grows. However, not many people realise that additional insulation isn't always the answer. In fact, too much insulation can be the secret cause of mould.
Leaving Too Many Gaps
One of the biggest problems DIY homeowners face is leaving too many gaps in their insulation. Gaps or insulation that isn't secured correctly can leave the building structure open to air and moisture leaks. Spray foam insulation is best for reaching into small cracks and any areas left open.
Cracks, holes, and gaps around the home can lead to a significant amount of heat loss. Especially around areas like your windows, it's estimated that poor air sealing can account for up to 30% of the air leaks in your home!
Typically the insulation would be situated below the slab and below the damp proof membrane for heavy duty use, whilst normal domestic buildings would have a higher performing, lower compressive strength material above the slab. How much space do you have? How much space you have is important.
Make sure an effective air barrier system is in place
The most important thing to do before installing fiberglass and rock wool batts in walls, and other parts of the building envelope, is to make sure there is an effective air barrier system in place.
Therefore, you should prioritize insulating your attic, especially its floor. Attic insulation keeps homes warm in the winter and cooler in the summer. Typically, attic insulation installers will use loose-fill or batt insulation in this area of your home.
Generally speaking, you only need to insulate the ground floor. If you're on an upper floor, you don't usually need to insulate your floor space. However, you should consider insulating any floors that are above unheated spaces such as garages, as you could be losing a lot of heat through those.
Insulating the interior walls of an old house can significantly improve its energy efficiency without compromising existing structures. The approach you take will depend on whether you're dealing with finished walls or open walls during a renovation.